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Malignant Arrhythmias in Critically Ill
V. arrhythmias
Ischemic HD
Cardiomyopathy
Heart Failure
Malignant Arrhythmias in Critically Ill
The long QT Syndrome,
RV Dysplasia,
Brugada Syndrome.
Ventricular Arrhythmias in:
Malignant Arrhythmias in Critically Ill
Preexcited A. Fibrillation
A. Flutter with 1:1 conduction
Incessant forms of SVT A...
Malignant Arrhythmias in Critically Ill
Adverse Effects of Dysrhythmias are
related to:
Underlying Heart Disease.
Potentia...
Malignant Arrhythmias in Critically Ill
Electrolyte & Acid Base derangements
Hypokalemia, Hypomagnesemia,
Alkalosis
Hypoxi...
Malignant Arrhythmias in Critically Ill
Empiric Pharmcologic Therapy.
DC External Cardioversion & Defibrillation
Surgical ...
Malignant Arrhythmias in Critically Ill
EP Guided Pharmocologic Therapy,
DC Internal Cardioversion,
Anti Tachycardia Pacin...
Malignant Arrhythmias in Critically Ill
Radiofrequency Catheter Ablation,
Implantable Cardioverter Defibrillators,
Cardiac...
Malignant Arrhythmias in Critically Ill
ECG Monitoring: Diagnostic limitations
HRV and QT Dispersion: Risk stratification
...
Torsade de points: Starts with long short
coupling intervals,
Polymorphic VT: R an T ventricular ectopics.
Supraventricula...
Lewis Lead
Intra atrial lead
Esophageal ECG
Special techniques:
Arrhythmias in Critically Ill
May not detect the full PR, QRS, or QT interval,
The waveforms generated may be so small that they
do not consistently tri...
Positional changes may lead to severe axis
shifts, which may be misleading if only one lead
is being monitored.
Loose elec...
Malignant Arrhythmias in Critically Ill
Programmed Electric Stimulation
Inducibility
Optimal drug selection
Candidates for...
Malignant Arrhythmias in Critically Ill
Arrhythmogenic Substrate,
Autonomic Modulation, and
Triggering Arrhythmias.
Target...
Malignant Arrhythmias in Critically Ill
 Improving Myocardial Ischemia
 Correcting Hypoxia, Alkalosis, Hypokalemia
 Red...
Malignant Arrhythmias in Critically Ill
 Adrenergically mediated: B-Blockers, Alpha, Beta
Blockers
 Vagally-mediated:
Va...
Xylocaine.
Amiodarone.
Procainamide Hcl
Pharmacologic Therapy:
Triggering Arrhythmias:
Arrhythmias in Critically Ill
Identify & correct abnormal homeostesis,
Suppress Triggering Arrhythmias,
Correct Overactive Autonomic System,
Terminate a...
Emergency Termination (ADENOSINE)
A short-acting drug (seconds) that is effective in
terminating AV nodal reentry tachyarr...
 Aminophylline is a competitive antagonist and
prevents the action of adenosine.
 If an initial bolus of adenosine does ...
Ventricular Tachycardia
Supraventricular Tachycardia with:
Aberrant conduction,
Preexisting BBB,
Antidromic conduction o...
ECG Differentiation:
 Fusion beats
 Capture beats
 V. ectopics having the same tachycardia
configuration recorded befor...
Left axis deviation
wide CRS > 14 sec
Monophasic QS in V1-V6
Suggestive markers
A-V dissociation with V. faster than A.
Ma...
Atrial flutter-fibrillation with frequent multrifocal VPCs
and ventricular group beats (indicated by arrows)
Sinus rhythm with frequent VPCs and ventricular
group beats (2 in a row)
A and B were obtained from the same patient with acute diaphragmatic MI. A. The
rhythm is sinus with first degree AV block...
Sinus rhythm with intermittent nonparoxysmal VT
(rate: 96 beats/min). None ventricular fusion beats
(FB). Leads II-a and I...
Malignant Arrhythmias in Critically Ill
1. Antiarrhythmic drugs
Quinidine, procainamide, disopyramide, ajmaline,
amiodaron...
Sinus rhythm with first degree AV block and frequent VPCs (V)
with R-on-T phenomenon leading to multiform VT (torsade de
p...
Malignant Arrhythmias in Critically Ill
1. Congenital Q-T prolongation syndrome
a. Jervell-Lange-Nielson syndrome
b. Roman...
Malignant Arrhythmias in Critically Ill
3. Intrinsic cardiac diseases
a. Myocardial ischemia and infarction b. Myocarditis...
Ventricular flutter with a rate of 214 beats/min
Atrial fibrillation with anomalous AV conduction because of
WPW syndrome, Ventricular tachycardia is closely simulated
In (C) a 12-lead ECG is depicted during sinus rhythm and
orthodromiccircus movement tachycrdia in a right free-wall and (D...
In the left panel, AV conduction of 2:1 is present, changing into 1:1 AV
conduction. The origin of the arrhythmia is low i...
Shown here is AF in a patient with the WPW syndrome (A). Note AV conduction
over the AP on the left and right side of the ...
Shown here is VT with a
relatively slow rate,
allowing the occurrence
of capture and fusion
beats. The tracing was
recorde...
Here, a VT shows a negative concordant pattern in the precordial
leads. This is diagnostic of VT. The QRS following termin...
Twelve-lead electrocardiogram in a patient with ventricular
preexcitation during AF with a rapid preecited ventricular res...
Typical characteristics of Torsade des Pointes. The initiation of the first
ventricular ectopic beat of hte tachycardia te...
Malignant Arrhythmias in Critically Ill
Arr. Underling PathologyAdverse effect
Sinus tachy. Acute MI. Worseing ishcemia
AF...
Malignant Arrhythmias in Critically Ill
Arr. Underling Pathology Adverse effect
Automatic AT Atrial Disease Incessant form...
The presence of frequent PVCs appears to
be associated with an increased risk of SCD in
patients with substantial LVdysfun...
Lown and Wolf classified PVCs into simple and
complex forms, with examples of the latter being pairs,
and early-cycle PVCs...
Subsequent studies showed the
shortcomings of warning arrhythmias. For
example, 155 (59%) of 262 patients with an
acute MI...
Furthermore, most recorded episodes of VT
result from midcycle rather than R-on-T PVCs,
and R-on-T PVCs initiated VT in on...
Malignant Arrhythmias in Critically Ill
It is the combination of Nonsustained VT or
frequent PVCs in patients with substan...
Malignant Arrhythmias in Critically Ill
The problem of sudden cardiac death (SCD)
resulted in the development of a device ...
Malignant Arrhythmias in Critically Ill
The limitations of Antiarrhythmic Drug
Therapy, recently amplified by data from th...
Malignant Arrhythmias in Critically Ill
Arrhythmia Surgery is restricted to those
who have discrete aneurysms and is usual...
 Cardiac Arrest due to VF or VT and not due to a
transient or reversible cause
 Syncope of Undetermined Origin with clin...
 Spontaneous Sustained VT.
 Nonsustained VT with CAD, prior LV
dysfunction, inducible VF, or sustained VT at
EPS testing...
 Pre-Event Trials
 Post-Event Trials
I) The AVID (Antiarrhythmics Versus Implantable
Defibrillator) Trial: is a multicenter trial intended
to compare the resul...
Not surprisingly, the ICD showed a survival
advantage for the patient population as a whole.
Over a mean follow-up of 18.2...
The Multicenter Automatic Defibrillator
Implantation Trial (1996). A multicenter trial that
studied a very carefully selec...
Three weeks removed from myocardial infarction,
Had Nonsustained VT on Holter (3-30 beats),
An EF of less than or equal to...
196 patients enrolled and randomized to either an ICD
or conventional therapy.
At a mean follow up of 27 months the trial ...
The Kaplan-Meier survival curve for the Mutlicenter Automatic Defibrillator implantation
Trial population shows the clear-...
Malignant Arrhythmias in Critically Ill
Patients in whom VT or VF is related to:
 Acute myocardial infarction,
 Transien...
Malignant Arrhythmias in Critically Ill
Those with psychological conditions who
would not be able to adapt to this type of...
Malignant Arrhythmias in Critically Ill
Those with incessant VT due to their poor
prognosis and continuous triggering of t...
Malignant Arrhythmias in Critically Ill
Ventricular Tachycardia can be modified not
only by Drugs but also by pacing or
Ca...
Malignant Arrhythmias in Critically Ill
Occasionally the tachycardia acclerates or
degenerates into VF. For this reason,
A...
Malignant Arrhythmias in Critically Ill
Initially, when the ICD was investigational, the
patients viewed this device with ...
Malignant Arrhythmias in Critically Ill
Once the ICD was implanted, however, their
outlook on life changed dramatically, b...
Malignant Arrhythmias in Critically Ill
What does the patient sense when the ICD
discharges?
If the patient has a hemodyna...
Malignant Arrhythmias in Critically Ill
Some patients note very little discomfort and
are barely aware that the device fir...
Malignant Arrhythmias in Critically Ill
Psychologically, Patients are disappoointed that
they had recurrence of the arrhyt...
Malignant Arrhythmias in Critically Ill
Kim et al., (1991) observed a total mortality
ratet of 17% at 1 year, and 29% at 3...
Malignant Arrhythmias in Critically Ill
Some investigators have questioned the
therapeutic value of ICD therapy as a whole...
Malignant Arrhythmias in Critically Ill
The defibrillator is superior to antiarrhythmic-
drug therapy in prolonging surviv...
Malignant Arrhythmias in Critically Ill
It would be unethical to withhold any therapy
with potential benefit from patients...
NEW THERAPEUTIC OPTIONS LIFE THREATENING ARRYTHMIAS
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NEW THERAPEUTIC OPTIONS LIFE THREATENING ARRYTHMIAS

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LIFE THREATING ARRYTHMIA MANAGEMNT

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NEW THERAPEUTIC OPTIONS LIFE THREATENING ARRYTHMIAS

  1. 1. Malignant Arrhythmias in Critically Ill V. arrhythmias Ischemic HD Cardiomyopathy Heart Failure
  2. 2. Malignant Arrhythmias in Critically Ill The long QT Syndrome, RV Dysplasia, Brugada Syndrome. Ventricular Arrhythmias in:
  3. 3. Malignant Arrhythmias in Critically Ill Preexcited A. Fibrillation A. Flutter with 1:1 conduction Incessant forms of SVT Automatic AT Uncommon type of AVNRT
  4. 4. Malignant Arrhythmias in Critically Ill Adverse Effects of Dysrhythmias are related to: Underlying Heart Disease. Potential for Progression (Degeneration). Refractoriness to Therapy.
  5. 5. Malignant Arrhythmias in Critically Ill Electrolyte & Acid Base derangements Hypokalemia, Hypomagnesemia, Alkalosis Hypoxia “Resp. failure, Pulm-Embolism” Sympathodrenal activation “endogenously secreted or exogenously administered”
  6. 6. Malignant Arrhythmias in Critically Ill Empiric Pharmcologic Therapy. DC External Cardioversion & Defibrillation Surgical Resection Classic Approach:
  7. 7. Malignant Arrhythmias in Critically Ill EP Guided Pharmocologic Therapy, DC Internal Cardioversion, Anti Tachycardia Pacing. Modified Approach:
  8. 8. Malignant Arrhythmias in Critically Ill Radiofrequency Catheter Ablation, Implantable Cardioverter Defibrillators, Cardiac Transplantation and Hopefully Gene Therapy Modern Approach:
  9. 9. Malignant Arrhythmias in Critically Ill ECG Monitoring: Diagnostic limitations HRV and QT Dispersion: Risk stratification Signal Averaged ECG: High negative and Low positive predictive valve
  10. 10. Torsade de points: Starts with long short coupling intervals, Polymorphic VT: R an T ventricular ectopics. Supraventricular tachycardia: Abrupt onset & abrupt termination. Routine monitoring: Record the initiation & termination of arrhythmias: Arrhythmias in Critically Ill
  11. 11. Lewis Lead Intra atrial lead Esophageal ECG Special techniques: Arrhythmias in Critically Ill
  12. 12. May not detect the full PR, QRS, or QT interval, The waveforms generated may be so small that they do not consistently trigger the detection device. Artifacts may lead to over counting of electrical events generated by the heart. Arrhythmias in Critically Ill
  13. 13. Positional changes may lead to severe axis shifts, which may be misleading if only one lead is being monitored. Loose electrodes may create artifacts resembling ventricular fibrillation or asystole Other mechanical activity such as gastric suction, teeth brushing, may be responsible for creation of artifacts. Arrhythmias in Critically Ill
  14. 14. Malignant Arrhythmias in Critically Ill Programmed Electric Stimulation Inducibility Optimal drug selection Candidates for ICD implantation.
  15. 15. Malignant Arrhythmias in Critically Ill Arrhythmogenic Substrate, Autonomic Modulation, and Triggering Arrhythmias. Targetted Against:
  16. 16. Malignant Arrhythmias in Critically Ill  Improving Myocardial Ischemia  Correcting Hypoxia, Alkalosis, Hypokalemia  Reducing Mechanical Overload Arrhythmogenic Substrate: Nitrates PTCA CABG ACEI Ang II Blockers β-Blockers
  17. 17. Malignant Arrhythmias in Critically Ill  Adrenergically mediated: B-Blockers, Alpha, Beta Blockers  Vagally-mediated: Vagolytic drugs, Pacing, Potassium-Channel- Blockers “Amiodarone”. Autonomic Modulation: α
  18. 18. Xylocaine. Amiodarone. Procainamide Hcl Pharmacologic Therapy: Triggering Arrhythmias: Arrhythmias in Critically Ill
  19. 19. Identify & correct abnormal homeostesis, Suppress Triggering Arrhythmias, Correct Overactive Autonomic System, Terminate arrhythmia. Treatment Algorithm: Arrhythmias in Critically Ill
  20. 20. Emergency Termination (ADENOSINE) A short-acting drug (seconds) that is effective in terminating AV nodal reentry tachyarrhythmias. Also used for diagnostic purposes. Causes transient complete AV block. Administered rapidly to maximize its negative dromotropic effect. Arrhythmias in Critically Ill
  21. 21.  Aminophylline is a competitive antagonist and prevents the action of adenosine.  If an initial bolus of adenosine does not cause AV block, the dose should be doubled until block occurs. Emergency Termination (ADENOSINE) Arrhythmias in Critically Ill
  22. 22. Ventricular Tachycardia Supraventricular Tachycardia with: Aberrant conduction, Preexisting BBB, Antidromic conduction over an A-V bypass tract. Arrhythmias in Critically Ill
  23. 23. ECG Differentiation:  Fusion beats  Capture beats  V. ectopics having the same tachycardia configuration recorded before the episode. Definite markers{ Arrhythmias in Critically Ill
  24. 24. Left axis deviation wide CRS > 14 sec Monophasic QS in V1-V6 Suggestive markers A-V dissociation with V. faster than A. Mainly EPS characterization ECG Differentiation: Arrhythmias in Critically Ill
  25. 25. Atrial flutter-fibrillation with frequent multrifocal VPCs and ventricular group beats (indicated by arrows)
  26. 26. Sinus rhythm with frequent VPCs and ventricular group beats (2 in a row)
  27. 27. A and B were obtained from the same patient with acute diaphragmatic MI. A. The rhythm is sinus with first degree AV block, APCs (X), and frequent VPCs (V) with group beats and a short run of VT. Leads II-a, II-b, II-c, and II-d are continuous. B. Soon after the tracing A was taken, the patient developed VT as a result of frequent VPCs with the R-on-T phenomenon. Leads II-a, II-b, and II-c are continuous
  28. 28. Sinus rhythm with intermittent nonparoxysmal VT (rate: 96 beats/min). None ventricular fusion beats (FB). Leads II-a and II-b are continuous
  29. 29. Malignant Arrhythmias in Critically Ill 1. Antiarrhythmic drugs Quinidine, procainamide, disopyramide, ajmaline, amiodarone, and lidocaine 2. Other drugs Prenylamine, phenothiazines, tricyclic antidepressant drugs A. Drug induced
  30. 30. Sinus rhythm with first degree AV block and frequent VPCs (V) with R-on-T phenomenon leading to multiform VT (torsade de pointes) and VF. The ECG abnormalities are fundamentally caused by quinidine-induced prolonged Q-T interval with broad T wave. Leads II-a, Leads II-a, II-b, II-c, and II-e are continuous.
  31. 31. Malignant Arrhythmias in Critically Ill 1. Congenital Q-T prolongation syndrome a. Jervell-Lange-Nielson syndrome b. Romano-Ward syndrome 2. Electrolyte disturbances a. Hypokalemia b. Hypomagnesemia B. Nondrug induced
  32. 32. Malignant Arrhythmias in Critically Ill 3. Intrinsic cardiac diseases a. Myocardial ischemia and infarction b. Myocarditis c. Bradyarrhythmias 1) Marked sinus bradycardia (e.g., sick sinus syndrome) 2) Advanced or complete AV block d. Mitral valve prolapse syndrome (MVPS) 4. Liquid protein diets 5. Central nervous system disorders (e.g., subarachnoid hemorrhage) 6. Hypothermia
  33. 33. Ventricular flutter with a rate of 214 beats/min
  34. 34. Atrial fibrillation with anomalous AV conduction because of WPW syndrome, Ventricular tachycardia is closely simulated
  35. 35. In (C) a 12-lead ECG is depicted during sinus rhythm and orthodromiccircus movement tachycrdia in a right free-wall and (D) anteroseptally located AP. ECG indicates electrocardiogram; and AP, accessory pathway.
  36. 36. In the left panel, AV conduction of 2:1 is present, changing into 1:1 AV conduction. The origin of the arrhythmia is low in the intra-atrial septum. AT indicates atrial tachycardial; and AV, atrioventricular
  37. 37. Shown here is AF in a patient with the WPW syndrome (A). Note AV conduction over the AP on the left and right side of the panel, with AV conduction over the AV node in the middle. As shown, the ventricular rate can become very high during AV conduction over the AP. In (B), a posteroseptal location of the AP is shown during sinus rhythm. AAAF indicates atrial fibrillation; WPW, Wolff- Parkinson-White; AV, atrioventricualr; and AP, accessory pathway
  38. 38. Shown here is VT with a relatively slow rate, allowing the occurrence of capture and fusion beats. The tracing was recorded in a patient with recent anterior wall MI. Note the QR pattern is several leads during VT, VT indicates ventricular tachycardia; and MI, myocardial infarction.
  39. 39. Here, a VT shows a negative concordant pattern in the precordial leads. This is diagnostic of VT. The QRS following termination of VT shows an old antero-apical MI. VT indicates ventricular tachycardia; and MI, myocardial infarction.
  40. 40. Twelve-lead electrocardiogram in a patient with ventricular preexcitation during AF with a rapid preecited ventricular response
  41. 41. Typical characteristics of Torsade des Pointes. The initiation of the first ventricular ectopic beat of hte tachycardia tends to occur following a pause. The QRS of this first beat initiates on the T wave making it difficult to appreciate where the T wave ends. There is a beat-to-beat change in the QRS axis in a sinusoidal pattern. The rate of hte tachycardia tends to be slower than the polymorphic VT seen ischemia
  42. 42. Malignant Arrhythmias in Critically Ill Arr. Underling PathologyAdverse effect Sinus tachy. Acute MI. Worseing ishcemia AF WPW Pseudo V. Tachy. HOCM Hypotenion Valvular HD P. Edema AF. Flutter PACs Hypokalemia Forerunners of AF PVCs Hyopkalemia Frequency, Salvos Hypomognesion Salvos AVNRT Fast slow pathway Incessant form
  43. 43. Malignant Arrhythmias in Critically Ill Arr. Underling Pathology Adverse effect Automatic AT Atrial Disease Incessant form Slow V. Tachycardia Reperfusion Arr. ? V. Tachycardia Acute MI rerperfusion VF Poly morphic VT Long QT Torsade de points
  44. 44. The presence of frequent PVCs appears to be associated with an increased risk of SCD in patients with substantial LVdysfunction (e.g. LV (LVEF < 0.4) but not in those without heart disease.
  45. 45. Lown and Wolf classified PVCs into simple and complex forms, with examples of the latter being pairs, and early-cycle PVCs or the R-on-T phenomenon. Complex PVCs were considered warning arrhythmias, i.e. arrhythmias that presaged the appearance of VF or VT.
  46. 46. Subsequent studies showed the shortcomings of warning arrhythmias. For example, 155 (59%) of 262 patients with an acute MI had warning arrhythmias, yet only 12 (7%) had primary VF, and 8 (40%) of 20 with primary VF had no warning arrhythmias.
  47. 47. Furthermore, most recorded episodes of VT result from midcycle rather than R-on-T PVCs, and R-on-T PVCs initiated VT in only 14 (15%) of 94 episodes in 1 study. Event in 47 patients with a history of VT, introduction of PVCs onto the T wave at EP testing, did not initiate sustained VT or VF.
  48. 48. Malignant Arrhythmias in Critically Ill It is the combination of Nonsustained VT or frequent PVCs in patients with substantial LVdysfunction (LVEF < 0.4) that identifies a high risk group for subsequent SCD, not the morphological aspects of the PVC itself.
  49. 49. Malignant Arrhythmias in Critically Ill The problem of sudden cardiac death (SCD) resulted in the development of a device by Mirowski and Colleagues in the late 1960s, with initial reports in the 1970s and the first human implantation in 1980s. History
  50. 50. Malignant Arrhythmias in Critically Ill The limitations of Antiarrhythmic Drug Therapy, recently amplified by data from the Cardiac Arrhythmia Suppression Trial (CAST) study, provided further support to the need for a Non Pharmacologic approach.
  51. 51. Malignant Arrhythmias in Critically Ill Arrhythmia Surgery is restricted to those who have discrete aneurysms and is usually not performed in those with diffuse aneursymal ventricles.
  52. 52.  Cardiac Arrest due to VF or VT and not due to a transient or reversible cause  Syncope of Undetermined Origin with clinically relevant hemodynamically significant sustained VT or VF induced at EPS testing, when prior drug therapy is ineffective, not tolerated, or not preferred . ACC/NASPE Guidelines, 1998
  53. 53.  Spontaneous Sustained VT.  Nonsustained VT with CAD, prior LV dysfunction, inducible VF, or sustained VT at EPS testing that is not suppressible by a class-1 antiarrhythmic drug. ACC/NASPE Guidelines, 1998
  54. 54.  Pre-Event Trials  Post-Event Trials
  55. 55. I) The AVID (Antiarrhythmics Versus Implantable Defibrillator) Trial: is a multicenter trial intended to compare the results of best medical therapy (Amiodarone or Sotalol) to a Transvenous ICD. The patient group targeted was the most seriously ill ventricular arrhythmia patient. Post-Event Trials:
  56. 56. Not surprisingly, the ICD showed a survival advantage for the patient population as a whole. Over a mean follow-up of 18.2 months the accrued death rates were 15.8+3.2% in the ICD group and 24+3.7% in the drug group. ICD: Clinical Trials
  57. 57. The Multicenter Automatic Defibrillator Implantation Trial (1996). A multicenter trial that studied a very carefully selected group of post MI patients who were at high risk for a future event. I) MADIT ICD: Clinical Trials
  58. 58. Three weeks removed from myocardial infarction, Had Nonsustained VT on Holter (3-30 beats), An EF of less than or equal to 35%, NSVT was inducible into Sustained Monomorphic VT or VF and Not suppressed with procainamide. Coronary artery disease patients ICD: Clinical Trials
  59. 59. 196 patients enrolled and randomized to either an ICD or conventional therapy. At a mean follow up of 27 months the trial was terminated prematurely at a time at which the ICD showed marked survival benefit over conventional therapy (39 deaths in the conventional therapy arm and 15 deaths in the ICD arm). ICD: Clinical Trials
  60. 60. The Kaplan-Meier survival curve for the Mutlicenter Automatic Defibrillator implantation Trial population shows the clear-cut advantage of the Implantable cardivoerter defibrillator over conventional therapy. Total mortality rate was reduced by 46% in the ICD group. Defibrillator Conventional Therapy 0 1 2 3 4 5 0.0 0.2 0.4 0.6 0.8 1.0ProbabilityofSurvival Patients, n Defibrillator 95 80 53 31 17 3 Conventional therapy 101 67 48 29 17 0 Year
  61. 61. Malignant Arrhythmias in Critically Ill Patients in whom VT or VF is related to:  Acute myocardial infarction,  Transient electrolyte abnormalities, or  Drug toxicity CONTRAINDICATIONS Implantable Cardioverter Defibrillators
  62. 62. Malignant Arrhythmias in Critically Ill Those with psychological conditions who would not be able to adapt to this type of therapy, Those with a short life expectancy due to terminal illness. Who Should not be offered an ICD? 1. 2.
  63. 63. Malignant Arrhythmias in Critically Ill Those with incessant VT due to their poor prognosis and continuous triggering of the ICD if sinus rhythm is restored intermitently. Patients with frequent long runs of nonsustained VT would also trigger frequent ICD discharges. Who Should not be offered an ICD? 3. 4.
  64. 64. Malignant Arrhythmias in Critically Ill Ventricular Tachycardia can be modified not only by Drugs but also by pacing or Cardioversion. This phenomonenon is familiar to every electrophysiologist who has attempted overdrive pacing of induced VT. ICD Related Prblems Exacerbation of the Arrhythmia:
  65. 65. Malignant Arrhythmias in Critically Ill Occasionally the tachycardia acclerates or degenerates into VF. For this reason, Antitachycardia Pacemakers without backup Defibrillator Capability were abandoned. Even during electrical cardivoersion, there is a similar risk of exacerbating the arrhythmia. Exacerbation of the arrhythmia:
  66. 66. Malignant Arrhythmias in Critically Ill Initially, when the ICD was investigational, the patients viewed this device with some skepticism. Most of the patients had few other options, therapy with antiarrhythmic drugs having failed while symptomatic arrhythmias continued. Psychosocial Aspects of The ICDs
  67. 67. Malignant Arrhythmias in Critically Ill Once the ICD was implanted, however, their outlook on life changed dramatically, becoming hopeful once again. They dervied a tremendous sense of security from the ICD, knowing that if the arrhythmia recurred, they would be rescued. Psychosocial Aspects of The ICDs
  68. 68. Malignant Arrhythmias in Critically Ill What does the patient sense when the ICD discharges? If the patient has a hemodynamically compromising arrhythmia, collapses, and immediately loses consciousness, there is no sensation of the discharge. Psychosocial Aspects of The ICDs
  69. 69. Malignant Arrhythmias in Critically Ill Some patients note very little discomfort and are barely aware that the device fired. Some patients report a very noticeable and sometimes painful shock. Most patients describe a somewhat uncomfortable or unpleasant internal twitch or shock. Psychosocial Aspects of The ICDs
  70. 70. Malignant Arrhythmias in Critically Ill Psychologically, Patients are disappoointed that they had recurrence of the arrhythmia but also glad to be alive. Patients with frequent discharges find them not only annoying but disconcerting. This situation requires revision of the antiarrhythmic regimen. Psychosocial Aspects of The ICDs
  71. 71. Malignant Arrhythmias in Critically Ill Kim et al., (1991) observed a total mortality ratet of 17% at 1 year, and 29% at 3 years. Winkle et al., (1989) reported a total mortality rate of 8%, 16% and 26% after 1, 2, and 5 years of follow-up respectively. Effect on Prognosis
  72. 72. Malignant Arrhythmias in Critically Ill Some investigators have questioned the therapeutic value of ICD therapy as a whole. ICD merely changes the mode of death, converting a “Sudden Death” into a “Nonsudden” Death, resulting in little or no prolongation of life. (Conversion Hypothesis). Effect on Prognosis
  73. 73. Malignant Arrhythmias in Critically Ill The defibrillator is superior to antiarrhythmic- drug therapy in prolonging survival among patiens resuscitated after symtpomatic, sustained ventricualr tachycardia or ventricular fibrillation causing hemodynamic compromise. It should be offered as first-line therapy to such patients.
  74. 74. Malignant Arrhythmias in Critically Ill It would be unethical to withhold any therapy with potential benefit from patients at very high risk. Thus, physicians continued recommending implantable cardioverter-defibrillator therapy for high risk patients but were uncertain about the magnitude of benefit. ICD: Clinical Bi-Impact

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